Gain insights into OOP with C#. Delve into practical coding examples and exercises, exploring OOP concepts through a real-world vending machine project to understand and apply them effectively.

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Object-oriented programming (OOP) has been around for decades. As the original object-oriented language, C# is a mainstay in the world of computer programming.

All the concepts of object-oriented programming that C# developers love to have in their arsenal are explained in detail along with relevant coding examples and exercises in this course.

This course is unique in its nature as it follows a project-based learning approach. Throughout the course, a real-world example of vending machine is followed to help the learners develop a firm understanding of the stated OOP concepts.

The learners will not only be able to play around with the project,  they’ll also be able to see all the concepts in action in this project.

Learn Object-Oriented Programming in C#

# The Terminologies
 Since we know that a new class is created *based* on an *existing* class  in inheritance, we use  the terminology below for the new class and the existing class:

* **Base Class (Mother Class or Superclass):** This class allows the *re-use* of its `non-private` members in another class.
* **Derived Class (Child Class or Subclass):** This class is the one that *inherits* from the superclass.


><img src="https://upload.wikimedia.org/wikipedia/commons/3/36/Light-311119_640.png" width="20" align="top"> A *child* class has **all non-private** characteristics of the *mother* class.

# What Does a Child have?


An object of the child class can use:

* All members defined in the **child** class.
* All `non-private` members defined in the **mother** class.

> <img src="https://upload.wikimedia.org/wikipedia/commons/9/97/Emblem-important-yellow.svg" width="25" align="top"> In C#, we can declare some classes non-inheritable using the keyword, `sealed`, like:
`public sealed ClassName {...}`.

# Implementation
In C#, to implement inheritance, we have to use the colon `:` operator. The generic syntax looks like the following:
```C#
SubClass : SuperClass{
//contents of SubClass
}
```

Let's jump back to our example of a `VendingMachine`. In a food vending machine, we have got several types of products e.g. beverages, chocolates, biscuits, etc. 
Now the noticeable thing here is that we always implement an inheritance relationship between classes when they have some of the attributes in common. For example, in the case of the products, all the products have names, prices, expiry dates, etc. Also, the *IS A* relationship stands valid in this case as we can say:
* A beverage *is a* product.
* A chocolate *is a* product.
* A biscuit *is a* product.

So, from the above discussion, we can conclude that if there is a base class named `Product`, we can derive the `Beverage`, `Chocolate`, `Biscuit`, etc. classes from it and can implement the specific attributes of these derived classes in them.

Let's derive and use the `Beverage` class in code:

In this lesson, you will learn how to use inheritance and the terminologies related to it.

Introduction to Object-Oriented Programming

Classes and Objects

Data Hiding

Inheritance

Polymorphism

Abstract Classes and Interfaces

Composition, Aggregation and Association

The Syntax and Terminologies

The Terminologies

What Does a Child have?